1. Field of the Invention
The invention relates to a system for casting, as well as to a method for casting.
2. Description of the Related Art
Such systems, having a casting apparatus, particularly for casting under a pressure produced by means of a gas phase, are used in foundry technology, particularly for the production of cast pieces having great physical and mechanical characteristic values, particularly made of light-metal alloys.
A pressure-casting method is known from DE 1178979 A, in which a melt is conveyed, under the effect of a pressure difference, from a furnace situated in a hermetically sealed feed chamber, through a casting pipe, into the cavity of a casting mold, whereby the casting mold is disposed in another hermetically sealed equalization chamber. The cast piece solidifies in the equalization chamber, at the temperature present there, and at the pressure present there. Subsequently, the finished cast piece is removed from the casting mold, and a new casting cycle can be carried out.
The counter-pressure die-casting method known to a person skilled in the art, also known as the CPC (Counter Pressure Casting) casting method, is a further development of the so-called low-pressure casting method, and is known from various documents, for example from EP 0 221 196 B1, EP 0 564 774 B1, or DE 34 22 121 A1.
However, in contrast to the low-pressure casting method also known to a person skilled in the art, compressed gas is applied not only to the casting furnace but also to the die or casting mold.
The actual casting process takes place, both in the low-pressure casting method and in the counter-pressure die-casting method, using a riser through which the melt is conveyed upward into the die.
However, in the case of the counter-pressure die-casting method, application of pressure to the melt in the furnace, for conveying the melt upward into the die, is brought about by means of a pressure difference, in that the gas pressure in the die is lowered slightly. As a result, an excess pressure occurs in the casting furnace, which pressure is sufficient for causing the melt to rise into the die.
It is a disadvantage of the known systems that some work steps, which are not directly connected with the actual casting process, are very labor-intensive. Furthermore, the change-over times, particularly for changing the casting mold or for recharging a furnace with melt, are relatively long.